Hot on Left, Cold on Right?

well the hot water would be in the tank, and most likely cooled down before the next flush. Also, i don't think you'd ever heat the whole toilet up to the point of melting that seal. They take quite a bit of heat to actually run.

And soften the wax seals?????

I think you will feel better about it quite a bit, even though it is no big deal. Sometimes the little things do matter.

Don Young

It applies to all plumbing, but really, it's not that big of a deal. If properly marked, it should not be an issue. You can buy red and blue hose bibb handles at the hardware store. Washing machines get hooked up once every 15 years or so, it's not like you're making hose connections there every day.

And the hot water would never touch the seal except during the flush.

Harry K

Yeah same in some Gulf states. No freezing temps of course. Low pressure mains water was accumulated from the street mains in a big tank at ground level in the yard. Then another pump raised that to another tank on the roof. Both tanks although painted white were out in the open with the sun beating on them. Identical systems for each living unit. By February too hot to walk across the tiled yard in bare feet by